Delta bridge (HZCB450) is a new type of large-span modular steel bridge that can be used to overcome obstacles such as large-span gullies and rivers. Delta bridge is a half-through bridge with a span of 35 to 81 meters in a single span. It can also achieve a multi-span design by adding pier supports, that is, the span length of the Delta bridge can extend infinitely. The deck of the Delta bridge can be made of steel and concrete. Steel decks are mostly used for semi-permanent modular steel bridges, while concrete decks are used for permanent bridges.
HZCB450 Modular Steel Bridge Main Technical Parameters
- Model: HZCB450
- Bridge truss height: 4.5m
- Net width of bridge deck: single lane 4.2m, double lane 7.35m
- Design span: span of a single span 36~81m
- Deck material: Steel deck or concrete deck
- Material: Q420qc,Q355
- Max. weight of unit component: 2378 kg
- Crane requirement: 35t; or 10t×10m truck crane
- Sidewalk: External or internal, support 1m, 1.2m, 1.5m sidewalk
- Design load: American Bridge Load Standard HS20-44, Chinese Bridge Load Standard Tracked vehicle 60 tons, Highway ClassⅠLoad
- Unit weight (steel deck): 2.63t /m (single lane),3.5t/m (double lane)
- Connection type: high strength friction grip bolts or high strength bearing bolts
The Structure of Delta Bridge
Delta bridge is mainly composed of upper chords, lower chords, triangular webs, cross beam, bridge deck and connectors, which belong to through bridge. The upper and lower chords of the main truss of Delta bridge are modular steel units with a cross-section of “H”, and the web members are modular units with an external shape of “K”. Between the two chords, the web and the web, and the web and the chord are all connected by compression and shear-type high-strength bolts through the gusset plate. This design reduces the non-elasticity deflection caused by the pin hole.
Features of Delta Bridge
- Simple structure, strong bearing capacity, small deflection, long service life and good overall appearance;
- Large span, the maximum single span of a single lane is 81 meters, and the maximum single span of a two-lane lane is 72 meters;
- Single hole span: 36m, 45m, 54m, 63m, 72m, 81m;
- External or internal sidewalks can be designed on both sides of the bridge;
- Delta Bridge can be used as a semi-permanent or permanent bridge;
- It can interface with the Bailey Bridge and install it using the Bailey Bridge (CB200) as a guide beam for erection.
The Erection Method of Delta Bridge
1. Temporary support method
The temporary support method is to build temporary support columns to support during the erection of a certain length of the main girder. After the erection of all modular steel bridges is completed, the temporary support columns are removed. If the modular steel bridge is designed with multiple spans as required, the piers should be constructed first, and then the support of the piers should be used for the erection of the Delta bridge.
2. Cantilever propulsion method
The cantilever propulsion method is a common method for modular steel bridge construction. This method is quick to erect, safe and reliable and does not require large-scale lifting equipment. Before the bridge is erected, a plain roller and rock roller are installed on both banks of the river in advance. Most of the components of the Delta bridge were assembled in advance on the rollers on the side of the push-out side, and then the bridge was pushed out smoothly and slowly by manpower or mechanical traction until it reached the rock roller position on the opposite bank. The CB200 Bailey panels are used as the launching nose when the Delta bridge is erected, and the number of launching noses is determined by the number of bridge sections.